On Wed, Jun 3, 2026 at 1:34 AM Markus Armbruster <[email protected]> wrote: > > Zhang Chen <[email protected]> writes: > > > Extend the 'IOThreadInfo' structure to include attachment metrics. > > This allows users to monitor the associated devices by identify them > > by their QOM paths. > > Should we mention block nodes and monitors, too? >
Good catch, will add the block nodes and monitors. > > > > New fields added to IOThreadInfo: > > @holders: IOThreadHolder of the devices currently associated with > > this iothread. Users can pre-allocate multiple iothread objects > > to serve as a persistent thread pool. When a device is hot-unplugged, > > it is detached from its iothread, but the iothread remains available, > > allowing future hot-plugged devices to attach to it. (Since 11.1) > > > > These fields are also exposed via the Human Monitor Interface (HMP) > > command 'info iothreads' to assist with manual debugging and > > performance tuning. > > > > Signed-off-by: Zhang Chen <[email protected]> > > --- > > iothread.c | 22 ++++++++++++++++++++++ > > monitor/hmp-cmds.c | 26 ++++++++++++++++++++++++++ > > qapi/misc.json | 11 +++++++++++ > > 3 files changed, 59 insertions(+) > > > > diff --git a/iothread.c b/iothread.c > > index a85e960e45..5949785b32 100644 > > --- a/iothread.c > > +++ b/iothread.c > > @@ -24,6 +24,8 @@ > > #include "qemu/error-report.h" > > #include "qemu/rcu.h" > > #include "qemu/main-loop.h" > > +#include "qapi/clone-visitor.h" > > +#include "qapi/qapi-visit-misc.h" > > > > /* > > * iothread_ref: > > @@ -119,6 +121,25 @@ static void iothread_unref(IOThread *iothread, const > > IOThreadHolder *holder) > > object_unref(OBJECT(iothread)); > > } > > > > +static IOThreadHolderList *iothread_get_holders_list(IOThread *iothread) > > +{ > > + IOThreadHolderList *head = NULL; > > + IOThreadHolderList **prev = &head; > > + GList *l; > > + > > + for (l = iothread->holders; l; l = l->next) { > > + IOThreadHolder *src = l->data; > > + IOThreadHolderList *entry = g_new0(IOThreadHolderList, 1); > > + > > + entry->value = QAPI_CLONE(IOThreadHolder, src); > > + > > + *prev = entry; > > + prev = &entry->next; > > + } > > If iothread->holders was a IOThreadHolderList instead of a GList, this > loop could be QAPI_CLONE(IOThreadHolderList, iothread->holders) instead. Nice comments, I will try it in next version. > > > + > > + return head; > > +} > > + > > static void *iothread_run(void *opaque) > > { > > IOThread *iothread = opaque; > > @@ -488,6 +509,7 @@ static int query_one_iothread(Object *object, void > > *opaque) > > info = g_new0(IOThreadInfo, 1); > > info->id = iothread_get_id(iothread); > > info->thread_id = iothread->thread_id; > > + info->holders = iothread_get_holders_list(iothread); > > info->poll_max_ns = iothread->poll_max_ns; > > info->poll_grow = iothread->poll_grow; > > info->poll_shrink = iothread->poll_shrink; > > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c > > index 443b8c785d..1b5883147b 100644 > > --- a/monitor/hmp-cmds.c > > +++ b/monitor/hmp-cmds.c > > @@ -237,11 +237,37 @@ void hmp_info_iothreads(Monitor *mon, const QDict > > *qdict) > > IOThreadInfoList *info_list = qmp_query_iothreads(NULL); > > IOThreadInfoList *info; > > IOThreadInfo *value; > > + IOThreadHolderList *h; > > > > for (info = info_list; info; info = info->next) { > > value = info->value; > > monitor_printf(mon, "%s:\n", value->id); > > monitor_printf(mon, " thread_id=%" PRId64 "\n", value->thread_id); > > + monitor_printf(mon, " holders="); > > + if (value->holders) { > > + for (h = value->holders; h; h = h->next) { > > + IOThreadHolder *holder = h->value; > > + > > + switch (holder->type) { > > + case IO_THREAD_HOLDER_KIND_BLOCK_NODE: > > + monitor_printf(mon, "[block-node: %s]", > > + holder->u.block_node.node_name); > > + break; > > + case IO_THREAD_HOLDER_KIND_QOM_OBJECT: > > + monitor_printf(mon, "[qom-path: %s]", > > + holder->u.qom_object.qom_path); > > + break; > > + case IO_THREAD_HOLDER_KIND_MONITOR_NAME: > > + monitor_printf(mon, "[monitor-name: %s]", > > + holder->u.monitor_name.monitor_name); > > + break; > > + default: > > + monitor_printf(mon, "[unknown]"); > > + break; > > + } > > + } > > + monitor_printf(mon, "\n"); > > + } > > monitor_printf(mon, " poll-max-ns=%" PRId64 "\n", > > value->poll_max_ns); > > monitor_printf(mon, " poll-grow=%" PRId64 "\n", value->poll_grow); > > monitor_printf(mon, " poll-shrink=%" PRId64 "\n", > > value->poll_shrink); > > diff --git a/qapi/misc.json b/qapi/misc.json > > index d9f82f0922..4c16be3fd4 100644 > > --- a/qapi/misc.json > > +++ b/qapi/misc.json > > @@ -137,6 +137,13 @@ > > # > > # @thread-id: ID of the underlying host thread > > # > > +# @holders: IOThreadHolder of the devices currently associated with > > This is rendered like > > • holders ([IOThreadHolder]) – IOThreadHolder of the devices currently > associated with > > Better use something like > > # @holders: the devices currently associated with ... > > I'm not sure about "devices", though. It's QOM objects, block nodes, > and monitors. Perhaps the QOM objects are all be devices (subtypes of > TYPE_DEVICE), but I'd have to dig through your patches to be sure. Does > it matter? Yes, you are right, will change the comments from "devices" to "QOM objects, block nodes or monitors". > > > +# this iothread. Users can pre-allocate multiple iothread objects > > +# to serve as a persistent thread pool. When a device is > > +# hot-unplugged, it is detached from its iothread, but the > > +# iothread remains available, allowing future hot-plugged devices > > +# to attach to it. (Since 11.1) > > This may need to be rewritten with block nodes and monitors in mind. OK. > > > +# > > # @poll-max-ns: maximum polling time in ns, 0 means polling is > > # disabled (since 2.9) > > # > > @@ -159,6 +166,7 @@ > > { 'struct': 'IOThreadInfo', > > 'data': {'id': 'str', > > 'thread-id': 'int', > > + 'holders': ['IOThreadHolder'], > > 'poll-max-ns': 'int', > > 'poll-grow': 'int', > > 'poll-shrink': 'int', > > @@ -185,6 +193,8 @@ > > # { > > # "id":"iothread0", > > # "thread-id":3134, > > +# "holders":[{"qom-path": > > "/machine/peripheral/blk1/virtio-backend", "type": "qom-object"}, > > +# {"qom-path": > > "/machine/peripheral/blk0/virtio-backend", "type": "qom-object"}], > > # "poll-max-ns":32768, > > # "poll-grow":0, > > # "poll-shrink":0, > > @@ -193,6 +203,7 @@ > > # { > > # "id":"iothread1", > > # "thread-id":3135, > > +# "holders":[{"qom-path": > > "/machine/peripheral/blk2/virtio-backend", "type": "qom-object"}], > > # "poll-max-ns":32768, > > # "poll-grow":0, > > # "poll-shrink":0, > > Would it be useful if one of these examples was a block node? OK, will update a demo for block node. Thanks Chen >
